Tuesday, September 6, 2011

Arcade Pushbutton Light Switch

UPDATE: If you would like to see different circuit design, have a look at version 2.

I was poking around the internets on Labor day when I came across this. It is a wall switch intended to replace a boring old toggle switch in your arcade room. My single arcade machine does not warrant its own room, but I do like the idea of an arcade button light switch. So, in an effort to get up and do something I made this arcade button switch for switching an extension cord. I have it plugged into the magnifier with fluorescent lamp on my electronics bench.

Since it was a holiday, I wanted to use only parts I had on hand so that I could finish this project the same day. Fortunately, I have a pretty large selection of bits that included arcade buttons. Sadly, I had no triacs, though and settled for a relay instead.

There are quite a few ways that you could make a set/reset flipflop circuit for this purpose. I settled on a 555 timer setup with relay. The flipflop could have just as easily been two NPN transistors, but I felt like reminiscing with the venerable 555 timer.

Download the schematic here if you like...

I very slowly drilled two holes in a cover plate.

Circuit assembly began with the relay I had on hand. I soldered some leads to the normally open contacts on the relay and put heatshrink on the solder joints. The unused, normally closed, pin on the relay was snipped off flush and insulated with a dab of hot glue. Otherwise, this pin would have been an exposed hot leg of 110VAC. Not a huge deal as everything is inside a plastic box, but it is a good idea to do.

Circuit assembly continued on a piece of perf board and was hot glued to the top of the relay which, in turn, was hot glued betwixt the arcade push buttons.

In the picture below, you can see where the hot lead of the extension cord is interrupted by the normally open contacts on the relay. You can also see a knot tied into the extension cord in the top left of the picture as strain relief.

Below you can see everything fits into the box nicely. What isn't too apparent is a pair of black wires coming out of the box too. I chose to use a wall wart transformer to power my circuit instead of the 110VAC coming into the box as this is just a bench top installation and not an, in the wall, permanent fixture.

Here is a video of the switch in action. You can see the camera adjusting it's auto white balance as the lamp I have the switch plugged into is turning on and off.

This project was a fun way to spend the afternoon. It certainly adds some geek cred to my electronics bench. I think I am more interested in a monostable 555 circuit attached to the relay output, however. That way, I could turn things on for a period of time and have them turn off automatically, instead of returning a day or two later to find out I left my soldering station on again.